In the field of metal packaging, typical containers are sealed by seaming a can end onto a can body using a well known double seaming process. The double seaming process is typically performed on a seaming system having a plurality of forming stations or seaming assemblies. Each assembly contains a rotatable seaming chuck that acts as an anvil to support the can body while two rotatable seaming rolls are brought into contact with the can end using a cam motion. The two seaming rolls define specific groove geometries that are configured to form a portion of the can body and a portion of the can end into a commercially acceptable double seam to thereby couple the can end to the can body.
Before the double seaming process, a can body is raised into engagement with a seaming chuck using a lifter chuck assembly or other positioning mechanism. After the double seam is formed, the positioning mechanism retracts, and the sealed container is ejected from the seaming chuck so that the seam-forming cycle can be repeated on another container. Ejection of the seamed container may be accomplished by the use of a knockout pad that taps a center panel of the container to knock the container out of engagement with the seaming chuck.
With current light-weight beverage cans, and/or with cans filled with low carbonated beverages, double-seamer speeds have been reduced to prevent can damage, such as body wrinkling. In some cases, filling speeds have been reduced to about 1150 cans per minute to avoid wrinkles in the can bodies.